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In Quebec, bacterial leaf spot of lettuce was observed for the first time in 1994. Since this first mention, the disease has been observed each year and the severity varied with environmental conditions. Little information was available on this disease because until recently it was only sporadically observed around the world following the first mention in 1918. In this project, we found that two groups of Xanthomonas caused the bacterial leaf spot of lettuce according to the BIOLOG profiles. From the results of strain characterization, a semi-selective medium has been developed to detect and quantify X. campestris pv. vitians. This medium is made of maltose, tryptone, methyl green, phosphate salts, amoxicillin, cephalothin, cycloheximide and trace elements. It allowed us to carry out studies on the ecology of the pathogen and on the disease epidemiology. The effect of weather conditions on bacterial population size and the bacterial leaf spot development has been studied. Weather parameters influencing the bacterial population were the number of hours with temperature higher than 28°C, the number of hours with wind velocity lower than 1 km per hour, the number of hours with relative humidity lower than 45% and the minimum relative humidity. The weather parameters that significantly discriminated between disease increase categories were the mean solar radiation, the number of hours with relative humidity higher than 90%, the mean relative humidity and the maximum temperature. Looking at the relationship between X. campestris pv. vitians population size and host plant development, it was shown that both bacterial population size and disease severity increased with leaf age. Mathematical models were developed to show these relationships. This information will be useful in disease management to decide when to apply bactericides and when to harvest. Finally, an exploratory study was conducted looking at the effects of nutrients on the size of saprophytic bacterial

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Both lettuce and pepper crops are routinely grown as transplants in Quebec. Previous research has shown that both of these plants respond well to endomycorrhizae with a resulting improvement in plant growth and yield. Although many studies have been conducted on endomycorrhizal inoculation of transplants most were looking at the end result, i.e. yields, and did not focus on changes occurring at the transplant stage. This series of experiments was conducted to look at the effect of inoculation at the transplant stage. Lettuce (Lactuca sativa cv. Parris Island Cos) and pepper (Capsicum annuum cv. Hybrid Bell Boy) were inoculated with Glomus intraradix Schenck & Smith and Glomus versiforme (Karst.) Berch. Experiments involved testing the effect of different growing media, different container volumes and different light sources on the growth of endomycorrhizal lettuce and pepper transplants. In all experiments the amount of growth enhancement due to endomycorrhizal inoculation was low or negligible. Colonization rates were generally low, probably due to low light levels. Transplants grown in larger volume containers were generally larger than those grown in smaller containers. The transplants grown in the soil and compost based media were larger than those transplants grown in the artificial media. Growth of lettuce and pepper transplants was affected differently depending on the light source used. Some interactions between the light source and the endomycorrhizal treatments was observed.

This research has focused on the determination of natural populations in the fields, the effect of different inoculum densities on lettuce growth and a study of the association of this fungus with two nematodes (Pratylenchus penetrans Cobb and Meliodogyne hapla Chitwood). Under conditions of artificial infestation of soil the results were satisfactory, but in trials with naturally infested soil the fungus could not be detected. The effect of different inoculum densities was measured at different stages of growth, and only in those plants inoculated 2 weeks after seeding were differences significant and consistent. Some evidence of the detrimental effect of wounding the root system prior to attack by the fungus led to studies of the relationship between this fungus with either P. penetrans or M. hapla. In the first case a negative interaction seemed to exist; no significant increase of the damage caused to the lettuce was observed. In contrast, when the root-knot nematodes and P. tracheiphilum were combined there was a marked reduction of lettuce growth. The interaction was found to be additive.

The aim of the research was to investigate the solid-state lighting parameters with natural lighting sources in horticulture effect on nutritional quality of baby leaf lettuce. The tasks of the research: 1. To investigate the effects of solid-state lighting on different leaf lettuce varieties nutritional quality in phytotron chambers. 2. To evaluate the impact on combination of blue and green light-emitting diodes with high-pressure sodium lamps lighting, at the stage of technological maturity, on the different varieties of lettuce internal quality in different growing seasons in greenhouses. 3. To evaluate the effect of supplemental 638-LED lighting, supplemental with natural and high pressure sodium lamps in greenhouse on the nutritional quality of lettuce in different growing seasons. 4. To investigate the effect of supplemental 638-LED lighting on the nutritional quality of lettuce lasting effect. / Tyrimų tikslas. Ištirti kietakūnio apšvietimo parametrų ir jo derinių su įprastiniais daržininkystėje šviesos šaltiniais efektus salotų maistinės kokybės valdymui. Tyrimų uždaviniai: 1. Fitotrono kamerose ištirti kietakūnio apšvietimo spektro efektus skirtingų veislių lapinių salotų maistinei kokybei 2. Gamybiniuose šiltnamiuose įvertinti kombinuoto mėlynų, žalių šviesos diodų su aukšto slėgio natrio lempomis apšvietimo, taikomo technologinės brandos tarpsnyje, poveikį skirtingų veislių salotų vidinei kokybei skirtingais auginimo sezonais. 3. Įvertinti trumpalaikį didelio srauto tankio raudonos LED (638 nm) šviesos, papildomos natūraliam ir aukšto slėgio natrio lempų apšvietimui šiltnamyje, poveikį salotų maistinei kokybei skirtingais auginimo sezonais. 4. Ištirti trumpalaikio papildomo raudonų 638 nm LED apšvietimo poveikio salotų maistinei kokybei išliekamąjį efektą.

Made available in DSpace on 2016-06-02T19:32:12Z (GMT). No. of bitstreams: 1 DissABG.pdf: 2489261 bytes, checksum: 65c0d87f1aabe3f9693bdb8719c132fb (MD5) Previous issue date: 2003-09-11 / Universidade Federal de Sao Carlos / The objective of this work was analyze the effects of aqueous extracts of Aristolochia esperanzae organs in the germination and early growth of lettuce and radish. All the prepared extracts obeyed the ratio of 100g of plant material + 300 mL of distilled water to produce an extract 100% concentrated. This extract was diluted with distilled water to produce final concentrations of 75, 50 and 25%. In the germination tests the extracts of leaf, stem, root, fruit and flower, with concentration of 100, 75, 50, 25% were evaluated. In the seedlings growth, extracts of leaf, stem and root were used in the concentration of 100 and 50%. In the germination tests, four replicates of 30 seeds were distributed in Petri dishes with two filter paper moistened with 5 mL of the extracts, dried during 12 hours and moistened again with 4,5 mL of distilled water. In the first test, the rate and germination percentage was evaluated. In the growth test, the seeds were previously germinated (2-4mm root length) and transferred to plastic boxes containing the filter paper or coconut fiber, moistened with the extracts. The aerial part height, root length, dry mass and the presence of abnormalities in the seedlings were evaluated. Both tests were maintained at constant temperature (27ºC). The obtained results showed that the leaf extracts affected strongly the germination percentage and all the extracts, in different concentrations, delayed the germination of lettuce and radish seeds. In the growth test could be verified that the stem and root extracts caused abnormalities in the seedlings. The seedlings grown in filter paper presented bigger growth inhibition in relation to seedlings from coconut fiber. The extract concentration was the main responsible for the incentive or inhibition caused on lettuce and radish seedlings growth. / O objetivo deste trabalho foi analisar os efeitos de extratos aquosos de diferentes órgãos de Aristolochia esperanzae na germinação e crescimento de alface e rabanete. Todos os extratos preparados obedeceram à proporção de 100g de material vegetal para 300 mL de água destilada, que produziu o extrato considerado 100% concentrado. A partir deste, foram feitas diluições com água destilada para 75, 50 e 25%. Nos testes de germinação foram avaliados os efeitos dos extratos obtidos de folha, caule, raiz, fruto e flor a 100, 75, 50 e 25% Para o teste de crescimento foram utilizados extratos de folha, caule e raiz na concentração de 100 e 50%. Nos testes de germinação foram utilizadas quatro repetições de 30 sementes distribuídas em placas de Petri forradas com duas folhas de papel de filtro umedecidas com 5 mL dos referidos extratos, secas durante 12 horas e reumedecidas com 4,5 mL de água destilada. No primeiro teste avaliou-se a porcentagem e velocidade de germinação das sementes. No teste de crescimento, as sementes foram previamente germinadas (2-4 mm de radícula) e depois transferidas para caixas plásticas contendo os substratos papel de filtro e fibra de coco umedecidos com os respectivos extratos. Avaliou-se a altura das plântulas, o comprimento radicular, a massa seca das plântulas, e a presença de anormalidades nas plântulas. Os testes foram mantidos a temperatura constante de 27ºC. Através dos resultados obtidos pode-se concluir que os extratos de folha foram os que mais afetaram a porcentagem de germinação e que todos os extratos e as diferentes concentrações retardaram a germinação de sementes de alface e de rabanete. Quanto ao teste de crescimento pode-se verificar que os extratos de caule e raiz causaram anormalidades nas plântulas. As plântulas crescidas no substrato papel de filtro apresentaram maior inibição do crescimento, em relação àquelas crescidas no substrato fibra de coco. A concentração dos extratos foi a principal responsável pelo estímulo ou inibição causada no crescimento das plântulas de alface e rabanete.

Made available in DSpace on 2014-06-11T19:28:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-01-27Bitstream added on 2014-06-13T19:37:24Z : No. of bitstreams: 1 hasegawa_jm_me_botfca.pdf: 900913 bytes, checksum: e49a35df3df1cebc7bd2e3139d7d52e2 (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Empresa Privada / O Bidens mosaic virus (BiMV) é um Potyvirus relatado pela primeira vez no Brasil, no Estado de São Paulo, onde foram realizados estudos através de microscopia eletrônica por Kitajima et al.(1961). É um vírus que causa sintomas em espécies de importância econômica como o girassol, a alface e a ervilha, além de algumas plantas ornamentais. Atualmente, embora se conheça o seu mecanismo de transmissão, a sua sintomatologia, as suas propriedades biológicas e físico-químicas e o seu círculo de hospedeiras, pouco se sabe sobre a importância do BiMV para a cultura da alface e a possíveis fontes de resistência em Lactuca sativa. O presente trabalho teve como objetivos a coleta de isolados de BiMV de diferentes regiões produtoras de alface no Estado de São Paulo, sua caracterização biológica, identificação por meio de técnicas moleculares e triagem de materiais de alface para resistência. Isolados virais coletados em plantas de picão-preto de regiões produtoras do Estado de São Paulo foram submetidos a diferentes metodologias de identificação e caracterização. Testes biológicos em hospedeiros diferenciais permitiram a diferenciação dos isolados de outros vírus de importância para a cultura da alface e a caracterização biológica de alguns isolados como BiMV. Foram vistas partículas flexuosas alongadas ao microscópio eletrônico de transmissão, sugerindo a participação de um Potyvirus na manifestação dos sintomas. O seqüenciamento direto de produtos de PCR de um isolado mostrou identidade de 96% com a seqüência de um isolado de BiMV coletado de ervilha. Isolados monolesionais multiplicados de BiMV foram inoculados em 89 cultivares de alface 2 de diferentes grupos varietais. A maioria das cultivares se mostrou resistente ao BiMV, exceto no caso das nacionais do tipo repolhuda lisa, que foram todas suscetíveis... . / Bidens mosaic virus (BiMV) belongs to the genus Potyvirus and was originally described in São Paulo, Brazil, under examinations by electron microscopy made on exudates obtained from infected plants by Kitajima et al.(1961). Some of the affected plants with economic importance are sunflower, lettuce, peas and bedding plants. Until now, transmission mechanisms, symptomatology on host plants, physical properties and host range had been reported, but few information are available about the importance of BiMV to commercial lettuce fields. At the present time there is no information on resistant cultivars in Lactuca sativa. The aims of this work was to collect isolates of BiMV from different commercial fields in São Paulo State; to determine their biological characterization and their identification by molecular methods and identify sources of resistance in lettuce by the screening of accessions for resistance. Virus isolates originated from different regions were submitted to various methods of detection and characterization. Tests on experimental host range provided data to differentiate one lettuce-infecting species to the others and the virus identification based upon symptom expression. Flexuous rods were observed in leaf extracts from infected plants, showing the presence of a Potyvirus as the causal agent of the symptoms. Direct nucleotide sequencing from amplified PCR products showed 96% of identity compared to an accession of BiMV at GenBank. Monolesional isolates of BiMV properly maintained and multiplied in propagational host were inoculated in 89 cultivars of lettuce of different horticultural types. The great number of them showed resistance to BiMV, except in the case 4 of the Brazilian butterhead types, all susceptible. At present, as the most important commercial lettuce cultivars exhibit high degrees of BiMV resistance, mainly in leafy and iceberg types, it is possible to affirm... (Complete abstract, click electronic address below)

Made available in DSpace on 2015-04-17T14:49:16Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1037555 bytes, checksum: a2a7db2a36b3246c8fbeaaacfc58b675 (MD5) Previous issue date: 2011-11-03 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Lettuce (Lactuva sativa) is the increased consumption of leafy vegetables in Brazil, however may be associated with the transmission of pathogenic microorganisms to human. The present study was to evaluate the microbiological quality of samples of curly lettuce variety, obtained from the traditional farming systems, organic and hydroponic sold in the city of João Pessoa, Paraiba, and verify the effectiveness of washing with sterile distilled water and sodium hypochlorite sanitizers 150 ppm and 1% acetic acid to reduce their bacterial load. We analyzed 60 samples for each cropping system, equally distributed between the bacteriological and parasitological tests, totaling 180 specimens. For bacteriological analyses, the samples were subjected to the determination of most probable number (MPN) of total and thermotolerants coliforms, total counts of mesophilic aerobic microorganisms and Salmonella sp. In holding the tests using spontaneous sedimentation parasitological, were surveyed primary structures of protozoa and helminthes. Salmonella sp. was not detected in the samples analyzed, regardless of cropping system. However, the results showed high contamination by mesophilic aerobic bacteria and total coliforms in samples of conventionally grown and organic, which also showed fecal coliforms counts higher recommended by the Brazilian legislation in 66% and 80% of the samples, respectively. For samples of traditional and organic crops was also observed high frequency of intestinal parasites, including pathogenic species Taenia sp. and Entamoeba histolytica. In contrast, only 20% of hydroponic lettuce samples were contaminated with intestinal parasites. The cleaning with sterile water was sufficient to reduce the bacterial load to safe levels only in hydroponic samples, already tested sanitizers were effective in reducing bacterial counts in all crops. / A alface (Lactuca sativa) é a hortaliça folhosa de maior consumo no Brasil, entretanto pode estar associada à veiculação de micro-organismos patogênicos ao homem. O presente estudo teve como objetivo avaliar a qualidade microbiológica de amostras de alfaces variedade crespa, obtidas a partir dos sistemas de cultivo tradicional, orgânico e hidropônico comercializadas na cidade de João Pessoa, Paraíba e verificar a eficácia da lavagem com água destilada estéril e dos sanitizantes hipoclorito de sódio a 150 ppm e ácido acético a 1% na redução de sua carga bacteriana. Foram analisadas 60 amostras para cada sistema de cultivo, distribuídas igualmente entre os ensaios bacteriológicos e parasitológicos, perfazendo um total de 180 espécimes. Para as análises bacteriológicas, as amostras foram submetidas à determinação do número mais provável (NMP) de coliformes totais e termotolerantes, contagem total de micro-organismos aeróbios mesófilos e pesquisa de Salmonella sp. Na realização dos ensaios parasitológicos através de sedimentação espontânea, foram pesquisadas estruturas primárias de protozoários e helmintos. Não foi detectada Salmonella sp. nas amostras analisadas, independente do sistema de cultivo. Porém, os resultados evidenciaram elevada contaminação por bactérias aeróbias mesófilas e coliformes totais nas amostras de cultivo tradicional e orgânico, as quais também apresentaram contagens de coliformes termotolerantes acima do preconizado pela legislação brasileira em 66% e 80% das amostras, respectivamente. Para as amostras dos cultivos tradicional e orgânico também foi observada alta frequencia de enteroparasitos, incluindo as espécies patogênicas Taenia sp. e Entamoeba histolytica. Em contrapartida, apenas 20% das amostras de alface hidropônica estavam contaminadas por enteroparasitos. A higienização com água estéril foi suficiente para reduzir a carga bacteriana a níveis seguros apenas nas amostras hidropônicas, já, os sanitizantes testados foram eficazes para redução das contagens bacterianas em todos os cultivos.

Made available in DSpace on 2015-04-17T14:49:44Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 649364 bytes, checksum: bf1a9bf925244349fb276f68b5a427fb (MD5) Previous issue date: 2010-09-22 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The search for a healthy diet consisting of vegetables consumed "in natura" just exposing the population to the risk of infections by bacteria and intestinal parasites. This study aimed to assess the bacteriological and parasitological of lettuce (Lactuca sativa) commercialized in supermarkets and public markets in João Pessoa-PB, comparing the quality of which are sold in supermarkets with the public markets. In this study 40 heads of lettuce, including 20 from four supermarkets and 20 from four public markets were submitted to two washes with sterile water, and subjected to bacteriological and parasitological analysis. Analyses showed that all samples had total coliforms but did not have Salmonella that 30% had fecal coliform above 1x102 MPN/g, and that intestinal parasites were present in 85% of vegetables, including Strongyloides spp., Giardia spp., E. histolytica / E. dispar. In public markets were found higher levels of bacterial contamination than the supermarkets (p > 0,05), but these two establishments showed no significant difference in the contamination with intestinal parasites. Due high contamination observed becomes necessary to establish laws limiting the presence of these contaminants so that the lettuce does not serve as a vehicle disseminator of disease by bacteria and intestinal parasites. / A busca por uma alimentação saudável composta por verduras consumidas in natura acaba expondo a população ao risco de contrair infecções por bactérias e enteroparasitas. Este trabalho teve como objetivo avaliar a qualidade bacteriológica e parasitológica de alface crespa tradicional (Lactuca sativa), comercializada em supermercados e mercados públicos de João Pessoa-PB, comparando a qualidade das que são comercializadas em supermercados com as de mercados públicos. Nesta pesquisa 40 pés de alface, dos quais 20 provenientes de 4 supermercados e 20 de 4 mercados públicos foram submetidos a duas lavagens com água estéril, e submetidos a análise bacteriológica e parasitológica. As análises mostraram que em todas as amostras havia coliformes totais sem, no entanto haver Salmonella, que 30% apresentaram coliformes termotolerantes acima de 2x102 NMP/g, e que os enteroparasitas estiveram presentes em 85% das hortaliças estudadas, entre os quais Strongyloides spp., Giardia spp., E. histolytica / E. díspar. Nos mercados públicos foram verificados níveis mais elevados de contaminação bacteriana do que nos supermercados (p > 0,05), porém estes dois estabelecimentos não demonstraram diferença significativa quanto à contaminação por enteroparasitas. Devido à elevada contaminação observada, torna-se necessário o estabelecimento de leis que limitem a presença de contaminantes para que desta forma a alface crespa não sirva como veículo disseminador de doença por bactérias e enteroparasitas.